not using specified methods that a sound estimate of the number of births prevented can be made. With regard to both propositions data are becoming available from program service statistics and sample surveys. A rough estimate of the proportion of families of reproductive age (operationally, females 15 to 44 years old) using contraception is available from cumulative data on family planning acceptors and/or users in several national programs (Figure 4). Enough is becoming known also about age, parity, age-specific natality rates, prior use of contraception, and other characteristics of acceptors and on length of use and effectiveness in preventing pregnancy of various family planning methods that, despite variations among LDC's on several of the important variables Year in Parerithesos is First Year of Program for Purposes of this Figure "Additional Estimated Users of Condoms and Spermicides 2345 YEARS SINCE START OF CURRENT PROGRAM Figure 4. Rate of acceptance of family planning in five national programs.d semi-autonomous status in the bureaucracy. In the long run, to the extent that contraceptive technology requires health services, family planning should be incorporated with other family health services. Provisions for such an eventual merger should be part of the planning and implementation of family planning programs from the start.